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Snowpetrel · 22-10-2018, 00:17

I've now got a nice batcar system complete off a bigger boat that has retrofitted a roller boom system.

Just looking at batten numbers and batcar spacings. Harken reccomends no more than 1.2-1.3 meters between cars to avoid luff flutter, but I'll end up with something more like 1.4 meters between cars as it stands at the moment.

To me 1.4 meters seems way to much, though it seems like many modern production boats have more than this sort of spacing.

What sort of slide spacing do you have and how does it work for you?

MartinR · 22-10-2018, 02:05

Congratulations to you and condolences to the other guy

I have 1.3 meters between battcars. 5 battens. Works perfectly. If I disconnect one car then it is 2.6 meters, which is too much. 1.4 meters will work without any problems. You do not want too many cars either, because of stack height.

Some production boats do not use intermediate cars, but I am not sure if the luff of the sail is different. Maybe there is a dyneema rope luff, so you can tension it better.
Battcars are expensive, and manufacturers save money where they can.

Snowpetrel · 22-10-2018, 05:02

Thanks Martin, good info. My brother just told me the Imoca 60's just cut a big hollow in the luff between the battens and attach the intermediates with bungy more to control the luff while dropping the sail, so maybe very big spacings can work. He also said the lower portion needed smallee spacing because it typically gets less tension due to the sail weight.

MartinR · 22-10-2018, 06:59

Of course, a little bit of luff hollow solves the problem.

**JPA Cate** · 22-10-2018, 12:35

You've probably thought of this already, but, if you're already stretching to get the main halyard on, the addition of the cars can make the stack so tall you'll need steps to get up high enough. On our boat, even with the step, Jim's the only one who can reach to snap the shackle on.

Ann

Snowpetrel · 22-10-2018, 14:03

^^I guess thats all part of the trade off, and it makes a lot of sense to keep the numbers of cars to a minimum. Lower stack height, less cost and less weight aloft . It's just finding the limits around maximum spacing, and if there are any additional dowsides, a big spacing also makes for a much wider stack and bigger flakes on the stowed sail. I also think more halyard tension and bigger reinforcing patches on the sail where the car attachment points are may be needed.

**JPA Cate** · 22-10-2018, 18:55

A chat to Steve Walker might help.

Ann

Snowpetrel · 22-10-2018, 19:19

^^I am sure it would, he knows his stuff. I am always reluctant to ask for advice from professionals when I don't intend to use them. Somehow it feels dishonest. What sort of slide spacing did he use on your main Ann? I guess with older style internal slides he may have kept the spacing closer to avoid overloading the slides.

Kestrahl · 22-10-2018, 22:34

1.4m should be fine provided your sail has a decent luff rope and its good to have 2 ply patches where the sliders attach.
That said a 50ft Lagoon has a 2 meter spacing with no luff rope and they use bungy to attach to the car so it doesn't pull the eye out of the sail. The bungy dies in the sun and the luffs do flutter pretty bad, but there is not a lot of load on the intermediates except when hoisting/dropping/flogging in strong breeze, when the sail is hoisted and set most of the load goes on the batten cars.
They also put the reefs below the battens. If there is a intermediate above a reefing point then it can take a bit of load, especially if the reef set back is not done correctly ( which is most of the time ).

Snowpetrel · 22-10-2018, 22:51

^^ Thanks Kestrahl. Very good Info.

I take it if I have understood what you've said they have about 4 meters between the battens and the intermediates are attached with bungy, not really taking any load when the sail is set. Makes my 1.4 meters sound small.

Snowpetrel · 23-10-2018, 04:57

I suppose the next question is number of battens. With a tall skinny main with a luff of 14.5 meters and a foot of 4.4 what are the pro's of 5 vs 4 Full length battens.

MartinR · 23-10-2018, 06:12

Good question. Traditionally (short tradition) the reefs would be just above the battens, so 3 reefs meant almost by default 5 battens.

Today things have changed. Probably to save money. I guess a sailmaker knows best.

There is also the good option of 3, 2 full and 2, 3 partial battens. Gives better control over sail shape with a cunningham. There is actual some control of sail shape with the leech line, if it is strong enough and preferably lead forward over a block.

**Jim Cate** · 23-10-2018, 13:03

Ben, with an P of 16.2 m we have three full and two longish plain battens. Sail shape and control are ok, and it saves some weight and friction over all 5 being full length. One bad side effect is that with our kinda stiff Hydranet sail, it is unruly when dropping, even with lazy jacks and a boom bag. Rather difficult to get it to come down neatly. I think this would be improved with the lower two full length, but haven't tried it to see!

Jim

Ambler · 23-10-2018, 15:38

Hi Ben
My thoughts on full batten mains stemmed from my experience on dinghys such as NS14 and Moths. I used North sails to build them many years ago as they were ahead of the pack with high aspect ratio rig set up.
Our boats use scaled up mainsails of those dinghys in that era. With the exception that the larger headsails on an IOR is the real driving force to keep the boat on task.
Happy to pull my main out on the lawn for you to look at next time you are up this way.
Wayne